Abstract

Background: Fine-needle aspiration cytology (FNAC) of the thyroid gland is practiced worldwide as a very economical and reliable diagnostic procedure. Objectives: To show the effectiveness of this inexpensive and simple procedure for the diagnosis of different thyroid lesions, particularly differentiation of malignant and benign lesions. We also sought to highlight the probable causes of error and possible remedies in the cases showing cytomorphological discrepancy.
Materials and Methods: A total of 180 cases of thyroid swellings were aspirated during our study period of 1 year (from November 2009 to October 2010). Cases were divided into six groups: (1) a nondiagnostic group where aspirate was inadequate and diagnosis was not offered; (2) a benign group that included different goiters and thyroiditis; (3) a group of lesions showing atypia of undetermined significance or follicular lesions of undetermined significance; (4) follicular neoplasm or suspicious of follicular neoplasm; (5) suspicious of malignancy; and (6) a malignant group that included nonfollicular malignant tumors of thyroid. Cases showing cytomorphological disparity were reevaluated.
Results: The overall accuracy of the technique was 88% with a sensitivity of 90.62%, a specificity of 85.71%, a positive predictive value of 89.65%, and a negative predictive value of 85.71%. Approximately 6% of cases could not be diagnosed because of inadequate aspiration. On histopathology, seven cases failed to show any cytohistological correlation.
Conclusions: FNAC is a minimally invasive, highly accurate, and cost-effective procedure for the assessment of patients with thyroid lesions and helps in differentiating lesions that require surgery from those that can be managed conservatively.